28 Apr 2022

Partial Discharge Coupling Capacitor for HV Rotating Machines Up-to 17kV

QUARTZTEQ, part of QUARTZELEC, has expanded its portfolio of LIFEVIEW condition monitoring solutions with the addition of the QCC17, a new partial discharge (PD) coupling capacitor designed specifically for HV rotating machines rated up to 17kV.

With PD monitoring for HV machines indicating insulation health, the newly developed QCC17 sensor bridges the gap between the existing QCC12 and QCC34 counterparts, ensuring cost-effective monitoring for any size machine. The sensor is now available from the LIFEVIEW range, allowing for a condition-based maintenance regime to be implemented across some of industry’s largest assets. 

“Our new offering sits neatly in the middle of our existing PD sensor portfolio and means we can now offer owner/operators of high voltage equipment more cost-effective support specifically for machines rated between 12kV and 17kV,” explained Seoras Shaw, Product Manager at Quartzteq. “This R&D project commenced in late 2019 and focussed on designing highly sensitive and reliable PD sensors for use on ‘mid-range’ machines rated up to 17kV.” 

The group’s LIFEVIEW solution for condition monitoring already offers online and offline monitoring in both safe and hazardous area environments, plus there is a range of compatible sensors and modules designed to measure PD, shaft voltage and airgap flux. Key features of the new QCC17 range include high electrical endurance and thermal stability, high sensitivity, a robust and compact design, compliance with UL 94V-0 requirements for fire resistance and self-extinguishing characteristic, along with applicable standards compliance and enhanced safety. 

Electrical Engineer for Quartzteq, Dr Benjamin Cella, explained the key issues addressed in designing a sensor built for reliability whilst conquering some of the fundamental challenges of partial discharge monitoring. “The harsh electrical and environmental constraints must be considered, as must restrictive installation area conditions. We have ensured product design compliance to European and International standards, which would prove the QCC17’s reliability and safety whilst remaining compact enough for ease of mounting.”

One specific development is the inclusion of the integrated voltage divider, which will also enable synchronisation to the HV supply. Whilst coupling capacitors with a higher capacitance have a higher sensitivity, too high a level can be detrimental to the correct distinction between PD and surrounding noise. 

Dr Cella further commented: “Our research, combined with multiple years of on-site experience and readings taken, have highlighted that values near 1nF are an appropriate compromise between effective PD monitoring for the majority of the machine winding and resistance to noise sources.”